Removes the deprecated support for token-less agents which
better secures the ironic-python-agent<->ironic interactions
to help ensure heartbeat operations are coming from the same
node which originally checked-in with the Ironic and that
commands coming to an agent are originating from the same
ironic deployment which the agent checked-in with to begin
with.
Story: 2007025
Task: 40814
Change-Id: Id7a3f402285c654bc4665dcd45bd0730128bf9b0
5b272b0c46